Spectrasonics Imaging, Inc. proposes a Phase II effort in collaboration with Riverside Research Institute (RRI) to develop a real-time ultrasonic, imaging system for indicating regions of the prostate that are suspicious for cancer. Real-time images produced by the system will enable better guidance of needle biopsies. Current ultrasonic guidance of biopsies has an unsatisfactory sensitivity and specificity for prostate cancer. As a consequence, the great majority of prostate biopsies are negative, resulting in an unacceptably high false negative rate. Studies by RRI suggest that the Spectral-Parameter Imaging (SPI) methods underlying the proposed system can improve detection of prostate cancer by 50 percent, which could detect 150,000 additional cancers annually in the US, reduce the need for repeat biopsies, and permit earlier initiation of treatment. The proposed SBIR study seeks to develop a real-time imaging system that uses color encoding to depict suspicious regions of the prostate. This color-encoding will be based on spectrum analysis of ultrasonic rf echo signals. We anticipate that biopsy efficacy can be markedly improved through increases in the sensitivity and specificity of such biopsy-guidance images. PROPOSED COMMERCIAL APPLICATION Over 1,000,000 prostate biopsies occur annually in the U.S. alone. Approximately 70 percent are negative, and over half of the negative biopsies are false. Repeat biopsies have almost the same incidence of positive biopsies as the initail exam. Unnecessary repeat biopsies and missed cancers impose an enromous dollar cost and patient risk. The proposed SPI methods appear capable of improving cancer detection by 50 percent which should prove clinically significant and commercially valuable.